The present invention relates to a device for indicating wear of the pads of friction material in so-called floating calipers used in the disc brakes of vehicle wheels and generally comprising a caliper body which is mounted so that it can slide axially by means of at least one hole on at least one guide pin, one end of which is rigidly connected, directly or indirectly, to the wheel stub axle, the axis of the guide pin and of the corresponding hole in the caliper body being perpendicular to the plane of the brake disc, a pair of pads positioned so that they straddle the disc, and a hydraulic piston which acts directly on one of the said pads and indirectly on the other pad, via the said caliper body.
As is known, the pads of friction material in the brakes are subject to wear and have to be replaced when their thickness falls below a minimum value in order to ensure safe braking.
Since these pads are carried by support shoulders which form an integral part of the brake bracket, and given that the latter is mounted in a position which is by no means easy for the driver to inspect himself, checks on the operational state of the pads are only carried out by specialist personnel on an occasional basis, with the risk that the check may be made only once the thickness has already worn beyond the minimum value permitted within the bounds of safety.
In order to overcome this disadvantage, devices for indicating the state of wear of the brake pads are already known within the state of the art, but such devices give the driver a solely visual signal once the state of wear of at least one pad exceeds a certain pre-established limit.
In addition, known warning devices have the disadvantage that they take up a lot of room around the brake caliper, where the space available is limited, and that they do not allow the pads to be replaced without first having to be removed.
The object of the present invention is therefore to provide a warning device that allows the change in thickness of at least one of the pads of a brake caliper to be monitored continuously, thereby giving the driver of the vehicle on which the brake is fitted a signal that lets him know the actual state of wear of the pad and that also enables the remaining mileage permitted by the pad to be calculated and thus displayed instantaneously.
A further object of the present invention is to devise a warning device which is compact and which allows the pads to be replaced without first having to remove it.